Nitric oxide (NO) has recently been identified as an important biological regulator involved in a number of diverse physiological processes such as blood pressure regulation, central nervous system communications, and the immunological destruction of tumor cells and parasites. Altered NO production has been implicated in a number of disease states ranging from cardiovascular disease to impotency. Recent studies have demonstrated that many of the functions of NO are mediated through the formation of s-nitrosothiol compounds (RSNO). The biological activity of s-nitrosothiols has been reported to include the following: